What was the age gap between dc3 and dc4

Just wondering those of you who had the first 3 dc close together and ended up having one more ,what age gap did you decide to have between last 2. Would be interesting to see as i don't really hear 4dc where 3 close in age then one further apart. But who knows?

23 months between dd1 and dd2. 19 months between dd2 and ds. 4 years between ds and dd3. She was not exactly planned! Working really well though. Big 3 are off at school and pre-school and dd3 has just fitted in. I'm loving doing all the baby activities again too, like having my first only this time I feel as though I know what I'm doing!

3-4 16 months. Biggest gap 2-3 22 months Ages now. 7,6,4,3 hectic but great too. I love it that they have a friend.12 years between me & my sister & we are very close but I missed having a sibling at home